Joseph Priestley (1733–1804) was an eighteenth-century English polymath with accomplishments in the fields of science, pedagogy, philosophy and theology. Among his more notable achievements were the discovery of oxygen and his work in establishing Unitarianism. Often a controversialist, Priestley's efforts to develop a 'rational' Christianity and support for the French Revolution eventually made him unwelcome in his native land. His 1807 Memoirs relate the story of his life until the time of his 1794 emigration to America and include other biographical materials written by his son. This first volume also contains five appendices discussing his philosophy, scientific work and religious opinions. Priestley's memoirs are an important source for anyone interested in the state of epistemology, rationalism, and religious belief in the age of the Enlightenment, and in a man who, in the words of his son, 'gave unremitting exertions in the cause of truth'.